"I have supported the mayor’s actions on Occupy Oakland. I think through this very very difficult time, her leadership has been important in showing a way forward that included a balance between first amendment rights and public safety," Cornu said.

In a statement, Quan did not say why Cornu decided to resign, only that she “has been a tremendous asset to my administration. We wish her well and Im [sic] grateful for her contributions.”

“I will restructuring my administration and making additional personnel announcements in the coming days,” the mayor wrote.

Cornu’s resignation was the second of the day. Quan's personal attorney and friend Dan Siegel resigned as her unpaid legal advisor at 2 a.m. Monday, when it became clear, he said, that a police raid on Occupy Oakland was imminent.

City Council members, business leaders, and the city's police union have blasted Quan for her response to the encampment, blaming her indecisiveness for allowing the protesters to re-establish the tent city in front of City Hall, after police first raided the camp on Oct. 25. They point out that the protests -- and the police response -- have cost the cash-strapped city millions of dollars. And their criticisms have lent strength to a recall effort that originally had the backing of only a small group of critics.

Quan has also lost the backing of some of her most loyal allies, including labor organizers who have participated in Occupy Oakland demonstrations. As a former activist and labor organizer, Quan’s decision to evict the tent city alienated many, including Cornu, who opposed the first police raid, according to sources inside City Hall.

Cornu had worked as a labor organizer for years, including as National Field Director for the AFL-CIO in 2010, before Quan appointed her to be senior policy advisor for intergovernmental relations in January. Cornu became deputy mayor in April.

Last week, The Bay Citizen learned that Nathan Ballard, a communications consultant hired by Quan, quit shortly after she allowed protesters to return to the plaza last month. City Hall sources said Ballard grew frustrated when Quan would not listen to his advice.

Like Ballard, Siegel said he became increasingly frustrated with Quan.

“[The mayor] works so hard to be elected and was obviously so proud and positive about it and became the first Chinese-American woman to be a mayor of a big city,” Siegel said. “And then she finds herself in the middle of something which obviously no one expected. And she just has not been able to deal with it well.”